Stoves for wood (DE-UZ 212)

The Blue Angel for stoves aims to encourage innovation in the sector and promote new developments in the design of stoves for the improvement of air quality. This will be achieved using equipment to lower emissions for an efficient and controlled combustion process with a significant reduction in the emission of particulate matter and other flue gases in comparison to conventional stoves. This includes:

• Separating technologies for reducing air pollutants that are harmful to human health, especially particulate matter and fine particles
• Automatic air regulation that largely avoids any user influence and incorrect use

To be certified with the Blue Angel, the stoves are subjected to an expanded test process that better reflects the real emissions from burning wood in the stove than is the case in the current type testing process. On this basis, stricter limits for pollutant emissions including the mass of the particulate matter have been defined. Heating appliances holding the Blue Angel must comply with a particle mass concentration limit of 15 mg/m3. The statutory limit according to the 1st BImSchV is 40 mg/m3. This reduction will be achieved above all through the use of a particle separator.

A large number of ultra-fine particles (smaller than 0.1 µm) are generated when burning wood that are considered to have a particularly negative impact on human health. No special and obligatory emission limits for these ultra-fine particles have existed up to now; the ultra-fine particles are currently included in the total amount of particulate matter. It would be better, however, to determine the number of ultra-fine particles. Therefore, the Blue Angel for stoves is for the first time calling for the introduction of a particle count limit for wood-burning stoves in order to protect human health. A measurement method has been developed for this purpose that is based on experience gained in combustion motors in the automotive sector and which has been specially adapted for the combustion of wood. A limit for the particle count concentration of 5.000.000/cm³ has been proposed on this basis and will be obligatory from 2022. The measurement method for determining the particle count will be validated during the transition period and tested in round robin tests.

Heating with wood causes significantly more air pollutant emissions than other energy sources such as heating oil or natural gas. It can result, therefore, in higher levels of particulate matter in the air in residential areas – especially if a lot of wood-burning stoves and fireplaces are operated at the same time in combination with weather conditions causing inversion. Therefore, cities and municipalities are introducing regional bans on conventional stoves (ban on the use of these stoves in pure air zones, ban on installing these devices in new housing developments) with exceptions for those appliances holding the Blue Angel.

It is important to note here that the use of stoves without the environmental label will still be permitted because there have currently been no changes for users outside of those zones where the burning of solid fuels is prohibited.